Easy-opening container panel structure



' April 29, 1969 F. J. STEC 3,441,171

EASY-OPENING CONTAINER PANEL STRUCTURE Filed March 1]., 1968 IN VENTOR FREDERICK J. STEC ATT'Y.

United States Patent EASY-OPENIN G CONTAINER PANEL STRUCTURE Frederick J. Stec, Oak Lawn, Ill., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Mar. 11, 1968, Ser. No. 712,198 Int. Cl. B65d 17/20 US. Cl. 220-54 4 Claims ABSTRACT OF THE DISCLOSURE A container having an easy-opening cover member. The cover member comprises a panel having a rectangular removable panel portion formed by scoring to provide a weakening line along which the removable panel portion is removed from the cover panel. A pull tab is secured to the removable panel portion and includes a penetrating nose which, upon tilting of the pull tab, initiates the severance of the weakening line. Further upward pulling of the pull tab completely separates the removable panel portion from the cover panel. A central rectangular depression is formed in the panel and arcuate beads are formed about each of the corners of the central depression for reducing the flexure of the removable panel portion.

The present invention relates to easy-open containers and more particularly to a new and improved container cover member having a removable panel structure of the full opening type.

Removable panel structures of the full opening type are usually formed by scoring the panel. The scoring provides a weakening line along which the removable panel section is separated from the cover panel. To facilitate removal of the removable panel portion, a pull tab is suitably pivotally mounted thereon. The pull tab includes a body portion having a penetrating end and a finger grip portion extending from the body portion. The pull tab is disposed on the removable panel portion so that the tab body is superposed over a portion of the removable panel portion which is coplanar with the remaining cover panel. The finger portion is disposed in a central depression formed in the removable panel portion. The tab body is formed with a penetrating nose which overlies the weakening line and serves to penetrate the latter along a localized area upon upward lifting of the rfinger grip portion. After the initial separation, the pull tab is pulled upwardly So that the remainder of the weakening line is severed and the removable panel portion separated from the cover panel.

Scoring of the panel to form the weakening line causes considerable displacement of metal inwardly into the removable panel portion resulting in undesirable flexure thereof. Heretofore, in circular removable sections it has been common practice to reduce the flexure by the provision of a coaxially disposed circular depression formed in the removable panel section. The depression forms in the nature of a well into which the finger grip portion of the pull tab extends as described above. The coaxial circular depression was adequate to reduce and substantially eliminate the flexure because of a uniform displacement of the metal resulting from the circular weakening line.

The problem of eliminating the flexure is particularly troublesome when the removable panel section is formed as a rectangle. The presence of the corners in the rectangular removable panel section causes a nonuniform displacement of the metal so that a greater portion of the displaced metal is located at the corners. In order to adequately reduce the flexure in these locations, a rectangular depression to accommodate the loose metal would "ice occupy a major portion of the removable panel portion so that only a limited surface area remains coplanar with the panel surface. This causes difficulties in mounting the pull tab, so that the length of the tab body is not completely supported on the removable panel section when in the nonuse position. This condition is objectionable because the tab would be tiltable relative to the panel and cause weakening of the hinge line about which the pull tab is adapted to fulcrum to perform its function as a lever to initially penetrate the weakening line. For that matter, under some circumstances it is possible that the hinge line could be weakened to the extent that the latter fractures whereby the pull tab separates from the panel.

. It; is a principal object of the present invention to overcome the difficulties encountered heretofore in connection with the formation of rectangular full opening removable panel portions.

This is accomplished generally by the formation in the removable panel portion of a substantially rectangular depression of which at least two of the opposing sides are respectively spaced from a corresponding pair of opposing sides of the removable panel section to provide suflicient surface area coplanar with cover panel surface for supporting the full length of the tab body to prevent rocking of .the pull tab. To reduce the flexure, indentations are provided at the corner of the panels of the rectangular depression.

In the drawings:

FIG. 1 is a top plan view of the container and cover member embodying the structure of the present invention;

FIG. 2 is a fragmentary cross-sectional view of the upper end of the container and the container cover member. taken generally along the lines 22 of FIG. 1; and

FIG. 3 is a cross-sectional view taken generally along the lines 33 of FIG. 1.

Referring now to the drawings, there is illustrated in FIG. 2 a conventional type container 10 of substantially obround cross-section and having mounted on the open end thereof a cover member 11 incorporating the structure of the present invention. Obround as used herein is intended to define a generally rectangular shape of which the sides of greater length are arcuate and the sides of lesser length are substantially straight and the corners are rounded as shown in FIG. 1.

The container 10 includes a container body 12 which may be formed of any suitable self-supporting material such as metal, cardboard or a composite thereof. Fixed to the open end of the container as by means of a single seam 13 is the cover member 11.

The cover member 11 is formed of metal and includes a chuck wall 14 extending upwardly from a cover panel 16. The cover panel 16 includes a removable panel portion 17 of substantially rectangular contour and to which a pull tab 19 is attached as by means of a rivet 18. The pull tab 19 functions as a lever to initially fracture the removable panel portion along a weakening line 21.

The weakening line 21 is formed in the cover panel 16 by a punching or scoring operation utilizing a standard type of scoring die. The resultant weakening line 21, as shown in FIG. 2, is of a generally trapezoidal cross-section. Disposed inwardly of the weakening line 21 and extending continuously about the removable panel portion 17 is an antifracture line 22 which is also formed by scoring and is of substantially the same shape but of lesser depth than the weakening line 21. The scoring means for forming antifracture line 22 is preferably incorporated on the same scoring die as used for the weakening line 21. Formation of the weakening line 21 and antifract-ure line 22 causes material to be displaced inwardly into the removable panel section 17, creating undesirable looseness and flexing thereof.

The loose material is particularly prevalent in the corners of the rectangular removable panel portion 17. To partially eliminate the looseness of material, a central depression 23 is formed in the removable panel 17. As shown, the depression 23 is shaped similarly to the configuration of the weakening line 21 and contour of the rectangular container body 12. However, the central depression 23 in the proportion shown is inadequate to sufiiciently reduce the undesirable looseness and fiexure of material in the corners.

In connection with the proportions of the rectangular depression 23, it is to be noted that the pull tab 19 includes a body portion 24 and a finger portion 26. The body portion 24 is disposed on the undepressed portion 28 of the removable panel section 17 and connected thereto by the rivet 18 so as to lie flush thereon in the nonuse position as shown. The rivet 18 is preferably formed integral with the removable panel portion 17. The body portion 24 is formed with a penetrating nose 29 which severs the weakening line 21 upon tilting of the pull tab 19 about a hinge line 31 defined between the ends of a U-shaped lance 32. To prevent rocking of the pull tab in its non-use position, It is essential that the body portion 24 lie flush on the undepressed surface of the removable panel section. Accordingly, it is not feasible to enlarge the rectangular depression 23 to further reduce the loose metal which is present in the corners of the removable panel portion 17, because the tab would be subject to rocking movement. Such rocking movement may result in weakening of the hinge line 31 and possible fracture therealong so that the pull tab becomes detached.

In accordance with the present invention the displaced metal in the corners is removed by indentations 33 at each of the corners. In the preferred form shown, the indentations 33 are in the form of arcuate beads symmetrically disposed between each of the respective corners of the removable panel portion 17 and the rectangular depression 23. The arcuately disposed beads 33 are dimensioned so that the ends of the pairs extending toward the pull tab 19 are spaced a distance sufiicient to accom- 4 modate the body portion 24 therebetween. In this manner sufficient fiat surface areas is available on the removable panel portion 23 to support tab body portion against rocking movement.

I claim:

1. In a container having an easy-opening cover memher, said easy-opening cover member comprising a panel, a rectangular removable panel portion defined by a weakening line formed by scoring said cover panel, a rectangular depression formed in said panel and located in the center of said removable panel section with the sides thereof disposed substantially parallel for reducing the flexure of the latter resulting from the formation of said scored weakening line, a pull tab including a body portion and a finger grip portion, means securing said pull tab to said removable panel portion with said body portion disposed between one side of said rectangular depression and an adjacent parallel side of said removable panel portion and with said finger portion disposed in said rectangular depression, and indentations formed in said removable panel section at each of the corners of said rectangular depression for further reducing the fieXure caused by said scored weakening line.

2. The invention as defined in claim 1 in which said indentations are disposed between the respective corners of said removable panel portion and said rectangular depression.

3. The invention as defined in claim 2 in which said indentations are arcuate and symmetrically disposed relative to each of said corners.

4. The invention as defined in claim 3 wherein the ends of the pair of said arcuate beads disposed between said sides supporting said pull tab body are laterally spaced to accommodate the width of the latter.

References Cited UNITED STATES PATENTS 3,232,474 2/1966 Dunn 220-54 3,366,270 1/1968 Khoury 220-54 GEORGE T. HALL, Primary Examiner. 

